Nakamichi NGXA80.4 User manual

User Manual

NGXA80.4

www.nakamichicaraudio.com

4-Channel Bridgeable Power Amplifier

65-C1517-MA CE7573() 145x210mm

OPERATION 9 EN

INTRODUCTION 2 EN

ACCESSORY LIST 2 EN

SPECIFICATIONS 2 EN

DIMENSIONS 3 EN

PANEL CONTROLS AND FEATURES 4 EN

WIRING DIAGRAM 5 EN

PRECAUTIONS 6 EN

FUSE REPLACEMENT 6 EN

PROTECTION CIRCUIT 6 EN

WIRING INSTRUCTIONS 7 EN

POWER CONNECTION LEADS 8 EN

Power Connection

Ground Connection

Remote Turn-On Connection

Speaker Connections

Gain = Input Level Control

X-Over Frequency Control

Crossover Switch

Bass Boost Control

No Function

No Sound

No Sound / Red LED Protection Shines

Poor Sound Quality (Distortions)

No Stereo Sound And A Weak Bass

HOW TO PROCEED IN CASE OF FAULTS 10 EN

INTERFERENCE 10 EN

INTRODUCTION

1 EN

Notes On The Power Supply

N-power Output @ 2 Ohm 110W x 4

N-power Output @ 4 Ohm 75W x 4

N-power Output @ 4 Ohm Bridged 250W x 2

Frequency Response 15Hz -30KHz

Input Sensitivity 200mV to 6V

T.H.D.

≤

0.2%

Low Pass Cross Frequency 50Hz - 3KHz

Remote Subwoofer Level No

Bass Boost 0dB 6dB 12dB

Minimum Impedance 20K

Fuse Size 30A x 2

Net Weight Approx. 3.1 kg

Dimensions ( L x H x W) 389x183x55mm

Max Power 2000W

Signal To Noise Ratio

≥

90dB

High Pass Cross Frequency 20Hz - 3KHz

2 EN

Thank you for your purchase, and welcome to Nakamichi! In order to enjoy the better

service from us, please keep your original invoice well and complete. You’d better post

the copy of back to the appointed service agent of Nakamichi so that you may get more

technical support.

1. User Manual 1pc

2. Amplifier 1pc

3. Mounting Screw (Ø4 x20mm) 4pcs

4. Wrench (2mm and 4mm) 2pcs

INTRODUCTION

ACCESSORY LIST

SPECIFICATIONS

3 EN

Dimensions(Unit: mm)

389 55

183

4 EN

Panel Controls and features

A. HIGH PASS CROSS FREQUENCY

Controls the frequency of the power amplifier of high frequency reduction to common denominat or is

20Hz to 3KHz.

B. X-OVER CONTROL

Depending on the selected switch setting the amplifier operates in fullrange, highpass or Lowpass mode.

C. LOW PASS CROSS FREQUENCY

Controls the frequency of the power amplifier of Low frequency reduction to common denominat or is

50Hz to 3KHz.

D. BASS BOOST LEVEL KNOB

The Bass BOOST feature will increase the sound level in the bass frequencies.

E. GAIN CONTROL

The gain control will match the amplifiers sensitivity to the source units signal voltage.

F. LOW LEVEL RCA INPUT

These RCA input jacks connect with your source unit RCA Low level outputs or via optional adapter with

your source unit speaker high level outputs. The use of high quality twisted pair car audio cables is

recommended to mind possibility of disturbance the audio signal.

G. SPEAKER CONNECTIONS

connect speakers/subwoofers to these terminals. Be sure to check wire for proper polarity. Never connect

the speaker cables to chassis ground.

H. Fuse

the fuses protect the car should a catastrophic problem occur in the amp. Always replace fuses with the

same size fuse.

I. Protection indicator

this red LED will light up and will be flashing if there is a fault presented to the amplifier. Please disconnect

the amplifier and resolve the fault before reconnecting the amplifier.

J. Power indicator

this LED will light up when amplifier works properly.

K. + 12V = POWER SUPPLY

connect this terminal through a fuse or circuit breaker to the positive terminal of the vehicle battery or

the positive terminal of an isolated audio system battery.

L. REM(ON/OFF) REMOTE CONTROL

when use Hi-Input, the amp can detect the DC offset from the high level input signal to auto turnON/OFF.

when the amp turns on , The REM terminal will output +12V DC to control the other device turn ON/OFF.

REM IN: When use Low level input , the amp rem in should be connected to the rem out of the source unit.

The head unit controls the amp turn ON/OFF.

N. GND(-) = GROUND CONNECTION

Connect this cable directly to the frame of the vehicle. make sure the metal frame has been stripped of

all paint down to the bare metal. Use the shortest distance possible. It is always a good idea to replace

the vehicle battery ground terminal or any other factory ground points.

M. INPUT MODE SWITCH

If your head unit has one single pair of rca outputs, input them in to the amplifiers channel 1 and 2 input

jacks and set the input mode switch to 2ch. The amplifiers preamp circuitry will automatically mix all the

channels and output will occur on all 4 channels.

If your head unit has two pairs of rca outputs, input front left and front right in to the amplifier channels 1 and

2 input jacks. Rear left and rear right in to amplifiers channels 3 and 4 input jacks. Set the input mode switch

to 4ch. The amplifiers preamp circuitry will automatically mix all the Channels and output will occur on all 4

channels.

A

B

C

D

E A

C G H

L

J

K N

I

B

MD

E

F

5 EN

WIRING DIAGRAM

CAR STEREO

REMOTE TURN ON

Terminal of head unit

CH2 SPEAKER

2~4 Ohm

CH4 SPEAKER

2~4 Ohm

CH1 SPEAKER

2~4 Ohm

CH2 SPEAKER

2~4 Ohm

CH1 SPEAKER

2~4 Ohm

CH3 SPEAKER

2~4 Ohm

CAR STEREO

REMOTE TURN ON

Terminal of head unit

SPEAKER

4~8 Ohm

6 EN

● This unit is designed for negative ground 12 Volts DC operation only.

● Use speakers with an impedance of 2Ω or 4Ω (4Ω to 8Ω when used as bridged amplifier)

● Avoid installing the unit where:

– It would be subject to high temperatures, such as from direct sunlight or hot air from

the heater.

– It would be exposed to rain or moisture.

– It would be subject to dust or dirt.

● If your car is parked in direct sunlight and there is a considerable rise in temperature

inside the car, allow the unit to cool off before operation.

● When installing the unit horizontally, be sure not to cover the heatsink fins with the floor

carpet.

● If this unit is placed too close to the car radio, an interference may occur. In this case,

separate the amplifier from the car radio.

● This power amplifier employs a protection circuit to protect the transistors and speakers

if the amplifier malfunctions.

●Do not attempt to test the protection circuits by covering the heatsink or connecting

improper loads.

● Do not use the unit with a weak auto battery as its optimum performance depends on a

normal battery supply voltage.

●For safety reasons, keep the volume of your car audio system moderate so that you can

still hear normal traffic sounds outside your car.

If the fuse blows, check the power connection and replace the fuse. If the fuse blows

again after replacement, there may be an internal malfunction. In this case, consult your

dealer.

WARNING:Use the specified amperage fuse. Use of a higher amperage fuse may cause

serious damage.

PRECAUTIONS

FUSE REPLACEMENT

This amplifier is provided with a protection circuit which operates in the following cases

when:

– the unit is overheated.

– the speaker terminals are short circuited.

PROTECTION CIRCUIT:

7 EN

POWER CONNECTION

The battery terminal (BATT) must be connected directly to the positive terminal of the

vehicle battery to provide an adequate voltage source and minimize noise. Connecting

the battery terminal lead to any other point (such as the fuse block) will reduce the power

output and may cause noise and distortion. Use only #4 gauge or thicker (smaller gauge#)

wire for this lead and connect it to the terminal of the battery after all other wiring is

completed.

GROUND CONNECTION

The ground terminal (GND) connection is also critical to the correct operation of the

amplifier. Use a wire of the same gauge as the power connection (#4 or thicker) and

connect it between the ground terminal(GND) of the amplifier and a metal part of the

vehicle close to the mounting location. This wire should be as short as possible and any

paint or rust at the grounding point should be scraped away to provide a clean metal

surface to which the end of the ground wire can be screwed or bolted.

REMOTE TURN-ON CONNECTION

The amplifier is turned on by applying +12V to the remote turn-on terminal (REM). The wire

lead to this terminal should be connected to the "Auto-Antenna" lead from the car stereo

which will provide the +12V only when the car stereo is turned on . If the car stereo does not

provide an "Auto-Antenna" lead, the remote turn-on lead may be wired to an "Accessory"

or "Radio" terminal in the car's fuse block. This will turn the amplifier on and off with the

ignition key, regardless of whether the car stereo is on or off. The remote turn-on lead does

not carry large currents. So #20 gauge wire may be used for this application.

SPEAKER CONNECTIONS

Depending on the type and number of speakers used with the amplifier wire them to the

speaker terminals as per the appropriate wiring diagram. For most applications # 18 gauge

wire should be used for the speaker leads but in no case thinner than # 20 gauge. For leads

is excess of 10 feet #16 gauge is recommended. When wiring the speakers, pay careful

attention to the polarity of the terminals on the speakers and make certain they correspond

to the polarity of the corresponding terminals on the amplifier. Do not ground any speaker

leads to the chassis of the vehicle.

WIRING INSTRUCTIONS

8 EN

POWER CONNECTION LEADS

NOTES ON THE POWER SUPPLY:

● Connect the +12V power input lead only after all other leads have been connected.

● Be sure to connect the ground wire of the unit securely to a metal part of the car.

● A lose connection may cause a malfunction of the amplifier.

● REM: The unit is turned on by applying +12 Volts to this terminal. This terminal does not draw

heavy current like the tow Power Terminals so a thinner connecting wire is acceptable.

Standard 18 GAUGE is fine and the standard color is yellow.

If the radio is equipped with a Power Antenna control wire, it can drive this terminal. If the

Power Antenna wire is already in use, you can still splice into it. With this method, the unit will

turn on automatically with the radio.

● Use the power supply lead with a fuse attached whose value is the same as original fuse.

● Place the fuse in the power supply lead as close as possible to the car battery.

● During a full power operation, Maximum current will run through the system. Therefore make

sure that the leads to be connected to the +12V and GND terminals of the unit respectively

must be larger than 10-Gauge (AWG.10).

BATTERY

DC 12V

To a metal part of car

HEAD UNIT

FUSE

(+12V)

SENS OUT

POWER

9 EN

GAIN = INPUT LEVEL CONTROL

● The input level control allows the system to work well within a wide range of output level.

Choose the adjustment in the way that you achieve a sound most possibly without any

distortion. As a guideline the following procedure is recommended:

–If you use several amplifiers, the adjustment has to be made for each set separately.

Tune in the volume of your car radio to 2/3 of the maximum volume. Now turn the gain

control of the amplifier from "Min" to "Max" direction until you can hear distortions. Then turn

the gain a little back until the noise disappear. The gain control adjustment is finished now.

ATTENTION: If you use 2 Ohm speakers in stereo mode, or 4 Ohm speakers in bridge mode

and the overload protection is triggered out, turn the gain control to "Min" direction, until

the operation is free of trouble.

X-OVER FREQUENCY CONTROL

● When the crossover control is in the Low-Pass position, this control becomes active

allowing you to select your crossover point.

● When the crossover control is in the High-Pass position, this control becomes active

allowing you to select your crossover point.

CROSSOVER SWITCH

Full: full range frequency.

Low pass: the lower frequency under setting point can be pass.

High pass: the higher frequency above setting point can be pass.

BASS BOOST CONTROLS

This amplifier has Bass controls for making good sound combination.

OPERATION

10 EN

No Function:

● The connection cable is not connected correctly (=terminal +12V/GND/REM). Ensure that

all connections and mechanic contact and that the jacket has been removed. The fuse is

defective-pay attention to the correct value of a new fuse!

No Sound :

● Speaker cable or speaker plug are not connected correctly.

No Sound / Red LED Protection is on:

● The plus and minus wires of the speaker cable have contact, thus eliminate the short

circuit. If you use a 2 Ohm speaker in stereo mode, a 4 Ohm speaker in bridge mode or

tri-mode and the set is overloaded, then turn the gain control to "min" until the operation is

free of trouble.

Poor Sound Quality (Distortions) :

● The speakers are overloaded, therefore turn down the volume level and check the

volume control positions.

No Stereo Sound And A Weak Bass :

● Speaker cables (+) and (-) are mixed up, unit wired out of phase.

HOW TO PROCEED IN CASE OF FAULTS

All cables can source and create interference. The power cable and Cinch/RCA audio

cable are very prone to interference; the remote cables are less prone. There is often

interference caused by the generator (piping), ignition (cracking) or other car electronic

parts. Most of these problems can be eliminated by correct and careful cabling. In doing so,

here are the following guidelines:

● Use only a screened audio cable for the wiring between "low level in" of the amplifier and

RCA or DIN output of the radio.

● Lay the signal, speaker and power cables separately with enough distance from one

another and also from each other car cable. If not possible, you can lay the circuit and

ground cable together with the serial cables. Audio and speaker cable should be as far

away from these as possible. The REM cable to the automatic antenna output of the radio

can be laid together with the signal cables.

● Avoid ground loops by laying the ground wiring of all components to a center point in a

starlike way. You can find the best central point in measuring the voltage directly at the

battery. Now compare this voltage value with the chosen ground point and the(+) terminal

of the amplifier. If measured voltage is only slightly different, you've found the correct

central. Otherwise you have to look for another point. You should measure with the ignition

point for earth being switched on and additionally switched on consumers (rear window

heating and light).

● If there are pickups from external electrical sources into the speaker cables, divide the

core leads and twist them together.

● If there are noises from the car electrics, add an interference suppression choke into the

power wiring.

● If there are humming noises, use thicker ground cables or add further ground cables to

the chassis.

● To reduce contact resistance and bad and loose contacts, please solder the cable ends

or use multi core cable ends, spade terminals or others. Gold Plated spade terminal are

free of corrosion and have the lowest contact resistance.

● Should all these measures be without any success, the use of a ground loop isolator may

solve the problem.

INTERFERENCE

www.nakamichicaraudio.com

Nakamichi NGXA80.4 User manual

Nakamichi NGXA80.4 User manual

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